1. Field of the Invention
The present invention relates to a substrate processing apparatus for performing heat processing and cooling processing for a substrate such as a semiconductor wafer or the like.
2. Description of the Related Art
In processes of semiconductor device fabrication, a layer insulating film is formed, for example, by an SOD (Spin on Dielectric) system. In this SOD system, a wafer is coated with a coating film by spinning the wafer, and chemical processing, heat processing, or the like is performed for the wafer to thereby form a layer insulating film thereon.
When a layer insulating film is formed by a sol-gel process, for example, first an insulating film material, for example, a solution in which colloids of TEOS (tetraethoxysilane) are dispersed in an organic solvent is supplied onto a semiconductor wafer (hereinafter referred to as xe2x80x9cwaferxe2x80x9d). Thereafter, the wafer to which the solution is supplied is subjected to gelling processing, and then exchange of solvents is performed. Subsequently, the wafer on which solvents are exchanged undergoes heat processing.
In a series of these processes, a variety of heat processing and cooling processing are performed. Commonly, the above heat processing and cooling processing are performed by placing a wafer on a hot plate or a chill plate (each referred to as a plate hereinafter) for subjecting the wafer to heat processing or cooling processing. However, on the grounds that the wafer is adversely affected by static electricity if the wafer is placed directly on the plate, a gap forming member is placed on the plate, and heat processing or cooling processing is performed for the wafer while a gap is formed between the wafer and the plate.
Incidentally, when the wafer which has undergone solvent exchange is subjected to heat processing at a high temperature in the above heat processing and cooling processing, processing is performed in a low-oxygen atmosphere in terms of the prevention of oxidation. Such a low-oxygen atmosphere is formed, for example, by exchanging an atmosphere inside a processing chamber for N2 gas after the wafer is transferred into the processing chamber.
There is a disadvantage that if the formation of a desired low-oxygen atmosphere by exchanging an atmosphere inside the processing chamber for N2 requires considerable time, the time required for heat processing in a low oxygen atmosphere is virtually lengthened, thereby exerting a bad influence on the total processing time to form an insulating film. Hence, it is desired to exchange the atmosphere inside the processing chamber for N2 gas efficiently.
An object of the present invention is to provide a substrate processing apparatus capable of performing heat processing in a low oxygen atmosphere in a short time and moreover shortening the total time required for substrate processing.
Another object of the present invention is to provide a substrate processing apparatus capable of performing heat processing in a low oxygen atmosphere uniformly.
To settle the above disadvantage, a main aspect of the present invention is a substrate processing apparatus, comprising a processing chamber for performing heat processing for a substrate having a first face and a second face, a hot plate, disposed in the processing chamber, for performing heat processing for the substrate from the second face side, a gap forming member for maintaining a predetermined gap between the front face of the hot plate and the second face of the substrate, and a first supply section, disposed around the hot plate, for supplying gas for purge nearly parallel to the substrate placed on the hot plate with a gap forming member between them and toward the first face and the second face of the substrate.
In the present invention, gas for purge is supplied nearly parallel to the substrate placed on the hot plate with the gap forming member between them and toward the first face and the second face of the substrate. Thus, an atmosphere around the substrate can be exchanged for the gas for purge efficiently, and moreover the atmosphere around the substrate can be exchanged uniformly. Accordingly, heat processing in a low oxygen atmosphere can be performed in a short time, and moreover the total time required for substrate processing can be shortened. Besides, heat processing in the low oxygen atmosphere can be performed uniformly.
These objects and still other objects and advantages of the present invention will become apparent upon reading the following specification when taken in conjunction with the accompanying drawings.